The cashier had already rung up Keri Wooster's items when she realized she didn't have her wallet. She dashed to her car and returned empty-handed to face the line of fidgeting customers she had kept waiting, a cell phone pressed to her ear. "Jordan, did you take my wallet out of my purse?" she asked in parental exasperation, as she made her way back to the checkout counter. "I'm holding up this line! You need to put things back where you find them."

Wooster, who has no children, was not actually talking to a Jordan, or indeed to anyone at all. But her monologue served its purpose, earning her sympathetic looks from the frustrated crowd at her local Wal-Mart.

Call Wooster a cellphony. She is a part of a growing number of people who are using their cell phones to carry on fake conversations to deceive or manipulate those around them. Some cellphonies use their cell phones to avoid contact with annoying coworkers or supervisors. Some pretend to be finishing a call when they arrive late for a meeting. The fake phone call has a technique all its own. Inexperienced cellphonies risk exposure with their limited repertoire of "uh-huhs." Sophisticated simulators achieve authenticity by re-enacting their side of an actual dialogue. Or they call voice-activated phone trees, so it sounds as if someone is talking on the other end.